1. Field of the Invention
The present invention generally relates to control systems used in manufacturing plants, and more specifically to a method and apparatus for remote management of field devices in a manufacturing plant.
2. Related Art
A manufacturing plant generally contains several field devices connected to a control system, which together implement a desired manufacturing process by controlling the operation of various equipment. Each field device in turn contains components such as sensors (which measure various variables such as temperature, flow, pressure, etc.), control elements (e.g., valves, switches), and transmitters (which transmit any desired information to a processing system, which controls the manufacturing process). For example, field devices containing pressure sensors may be monitored and valves controlled to maintain the pressure level in a boiler (in general equipment) at a desired value.
Field devices are often connected to a central location containing a field device management station (FDMS) and several clients. The FDMS and the clients together are used to manage (e.g., configures, controls, etc.,) the field devices. The clients are generally connected to the FDMS by a wire-based medium. Operators located at the central location may manage field devices by issuing commands using the clients and/or FDMS. Typically, the commands are transferred to the server on the wire-based medium, and the FDMS sends the commands to the field devices according to the medium/protocol (e.g., HART protocol, Foundation Field Bus Protocol) using which the field devices are connected.
There is often a need to remotely (i.e., away from the central location) manage the field devices. For example, assuming that a field device is not responding to specific commands sent via a FDMS, it may be desirable for an operator to be physically close to the field device and issue specific commands, thereby being in a position to directly observe the response of the field device.
In one prior approach, an operator is provided a portable device which directly connects to a field device of interest by a short lead/wire, and the operator may issue commands (including instructions which are together referred to as a ‘method’ in the relevant arts) from the portable device. Thus, the operator can issue various commands by being in close physical proximity to a field device of interest.
One problem with such a prior approach is that any changes that the operator performs may not be propagated accurately/immediately to the FDMS (and possibly an associated database which maintains the status of various field devices). The inconsistency between the status of field devices and the information at the FDMS may be undesirable at least in some environments. In addition, the operator may not be able to able to physically go very close to a field device of interest to secure the connection (from the portable device), for example, because of hazardous material around in a disaster situation.
What is therefore needed is an improved method and apparatus which enables an operator to remotely manage field devices in a manufacturing plant.